Frozen orbitals

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7 years 4 months ago - 7 years 4 months ago #333 by Ziaei
Frozen orbitals was created by Ziaei
Dear Mihaly,

I would like to run a single reference eom-ccsd calculation with 10 occupied orbitals and only 100 virtual orbitals, and further want to freeze higher lying virtual orbitals.

Is such kind of calculation possible with mrcc ?

I was unable to find the according keywords in order to be able to freeze specific number of occupied and unoccupied orbitals for a single reference eom-ccsd calculation.

For instance in PSI4 we have the following keywords :

set FROZEN_DOCC [131]
set frozen_uocc [408]

Bests
Vafa
Last edit: 7 years 4 months ago by Ziaei.

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7 years 4 months ago #334 by kallay
Replied by kallay on topic Frozen orbitals
Dear Vafa,
You can freeze any number of occupied orbitals with the core keyword. The freezing of virtual orbitals is more complicated. You should formally run a MR calculation with setting the higher lying virtuals to inactive and excluding excitations to inactive orbitals. That is, for (EOM-)CCSD:
nacto=10
nactv=100
maxex=2
maxact=on
0 0

Best regards,
Mihaly Kallay
The following user(s) said Thank You: xwang862

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2 years 6 months ago #1160 by xwang862
Replied by xwang862 on topic Frozen orbitals
Just to report my result in case anyone is still searching for an answer.

I had the same question as Vafa, i.e. freezing both occupied and virtual in a single-reference (EOM-)CCSD calculation. Mihaly's solution solved it! Just don't forget `nacto` and `nactv` are specified as the number of spin orbitals (I got the number wrong in my first trial).

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